This study was initiated to understand the mechanism of chemically induced cell differentiation in neoplasia. The research is directed at present to determine: (1) the effect of dimethylsulfoxide (DMSO), bisacetamides, hormones, and other selective compounds (including antitumor agents) on the expression of oncofetal markers in hepatoma and leukemia cell lines from animal and humans; (2) the expression of oncofetal markers in premalignant hepatocyte populations; (3) the reversibility of the neoplastic state when these cells and cell lines are exposed to the above mentioned agents.